Wednesday, my air--pipe -- and some of my fittings -- arrived, so I put a bit of time into running more pipe, and connecting up a few more things.
That's one from the footbrake valve to the 'original' brake servo, and also one out to the trailer relay valve. Still waiting on my other fittings to turn up, probably going to chase the order up and see what's happening.
Flush with success from that, and having not crippled myself enough crawling around on the floor, I decided to tackle the offside side-marker lights. Two marker light brackets welded onto the side of the body... Oh, and welded the rear wing back on, while I was in the area; since I leant on it and reminded myself that it wasn't actually attached to anything other than its brace strut.
I didn't get any photos of the brackets in the fitting, because it was dark on that side of the truck and there's not much to see anyway; it's just taking the little Rubbolite brackets, and welding them to the body.
They're spaced exactly like the other side are, with one at each extreme end of the body, and two more in the middle. You'll notice I only mentioned welding on two of them; I only had three of those brackets available to begin with, and I wanted to use them for the 3 rearmost lights. And then I decided I didn't want to crawl into the tiny space available to weld on the last light, because I was getting cold n creaky.
I did, however, wire and build up all the lamps themselves so I could turn the lights on and see that comforting amber glow.
Nice!
And then Friday got a surprise extra 5 hours of overtime tacked on it, thanks to someone driving a loaded 8-wheeler off the road and nearly laying it on its side in a farmer's field; and I clocked off at a quarter to 11 at night, so there was no tinkering time that day. Saturday, I was very definitely feeling the wear n tear of the extended work-week; so there was no tinkering time then either, after I got back from work in the morning.
Sunday, however...
Yeah, I think it's good. But I also think it's ... missing something.
I am a little put out by the two 'A's being different, but I will live with it for now and if I truly grow to hate it I'll just paint over it and try again.
Anyway, then I decided I needed just a little more...
Of course, this was a little more perilous to paint, and I'm even more put out by the end result of the smaller letters. But, again, if I truly decide I hate it, it's only paint and I can make it go away.
Extremely happy with how the numbers came out tho. 
I keep looking at it through the lens of "what can I do better next time". It'll never be perfect, hand-painted signwriting never is and that's part of the charm of it, and I certainly don't have the decades of experience of the professionals.
(... "each wincn", though... )
Fittings & piping: relay valve is almost all hooked up, quick-release valve just loosely dangling in place until I make a bracket to fix it to; I've run the air-lines for the gauges up into the dash, so they're ready to be connected up, as soon as I make the air-tank manifolds.
Once again it comes down to waiting for a paycheck to land so I can buy material & parts to do the next steps. (Aluminium for tank manifolds, compressor belts, hard-line from compressor to dryer/regulator/unloader, etc.) I am somewhat anxious to see everything come together and -- hopefully -- work!
Also debating setting up a tripod and recording a time-lapse of me laying out & lettering the other side of the boom, at some point. Could be quite neat, I think. (But then that means editing video, ugh. (Might do it anyway though.))